Find the empirical formula of a compound which contains 54.93% potassium, 38.73% boron and 6.34% hydrogen.A.
KBH
B.
KB2H4
C.
KB3H9
D.
K2B5H9

Answers

Answer 1
Answer: Use the percent as mass in g 
Mass g) --> g/mol 
K, B and H molar mass from periodic table

54.93 g K x (1 mol K/ 39.10 g K) = 1.405 mol K
38.73 g B x (1 mol B/ 10.81 g B) = 3.583 mol B
6.34 g H x (1 mol H/ 1.008 g H) = 6.290 mol H

Divide all three answers by the smallest value and you will get 
1.000 mol K
2.550 mol B
4.477 mol H 
now multiply these three answers by a number that will make all a whole number or (a number with a 9 as the first decimal point)
so multiply by 2
2 mol k
5 mol B
and 9 mol H
E.F. = K2B5H9 
Answer is D 
Sorry for bad explanation!!!!!!


Answer 2
Answer:

Hello!

Find the empirical formula of a compound which contains 54.93% potassium, 38.73% boron and 6.34% hydrogen.

A.     KBH

B.     KB2H4

C.     KB3H9

D.     K2B5H9

  • We have the following data:

Potassium (K) ≈ 39 a.m.u (g/mol)

Boron (B) ≈ 11 a.m.u (g/mol)

Hydrogen (H) ≈ 1 a.m.u (g/mol)

  • We use the amount in grams (mass ratio) based on the composition of the elements, see: (in 100g solution)

K: 54.93 % = 54.93 g

B: 38.73 % = 38.73 g

H: 6.34 % = 6.34 g

  • The values ​​(in g) will be converted into quantity of substance (number of mols), dividing by molecular weight (g / mol) each of the values, we will see:

K: (54.93\:\diagup\!\!\!\!\!g)/(39\:\diagup\!\!\!\!\!g/mol) \approx 1.408\:mol

B: (38.73\:\diagup\!\!\!\!\!g)/(11\:\diagup\!\!\!\!\!g/mol) \approx 3.521\:mol

H: (6.34\:\diagup\!\!\!\!\!g)/(1\:\diagup\!\!\!\!\!g/mol) = 6.34\:mol

  • We realize that the values ​​found above are not integers, so we divide these values ​​by the smallest of them, so that the proportion does not change, let us see:

K: (1.408)/(1.408)\to\:\:\boxed{K = 1}

B: (3.521)/(1.408)\to\:\:\boxed{B \approx 2.5}

H: (6.34)/(1.408)\to\:\:\boxed{H \approx 4.5}

convert number of atomic radio into whole number

2 * (1 : 2.5 : 4.5)

= 2 : 5 : 9  ← whole number of atomic radio

K = 2

B =  5 

H = 9

  • Thus, the minimum or empirical formula found for the compound will be:

\boxed{\boxed{K_2B_5H_9}}\Longleftarrow(Empirical\:Formula)\:\:\:\:\:\:\bf\green{\checkmark}

Answer:

D.     K2B5H9

________________________

\bf\blue{I\:Hope\:this\:helps,\:greetings ...\:Dexteright02!}\:\:\ddot{\smile}


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Temperature is directly related to the speed of the molecules such that as the temperature decreases, so does the speed of the molecules. When the balloon was placed in the freezer, the temperature plummeted and so the molecules moved less. Due to this lack of movement, less space was used by the balloon so it shrunk.

Which of these changes produces the greatestincrease in entropy?
(1) CaCO3(s) --> CaO(s) + CO2(g)
(2) 2 Mg(s) + O2(g) --> 2 MgO(s)
(3) H2O(g) --> H2O(l)
(4) CO2(g) --> CO2(s)

Answers

Answer:

Was this correct? I am pretty sure it is since you are going from a solid to a gas in the first reaction.

Explanation:

(1) CaCO3(s) --> CaO(s) + CO2(g) --- solid to solid & gas ** most entropy here

(2) 2 Mg(s) + O2(g) --> 2 MgO(s) solid & gas to a solid

(3) H2O(g) --> H2O(l) gas to a liquid

(4) CO2(g) --> CO2(s)   gas to a solid

As temperature rises and a substance transforms from a solid to a liquid to a gas, entropy increases. Because they have the most flexibility to move, gases have the highest entropy values. Here the first reaction has high entropy. The correct option is 1.

The level of unpredictability in a system is known as entropy. The degree of randomness is highest when comparing the three forms of matter solid, liquid, and gas because the gas particles move freely.

(1) CaCO3(s) --> CaO(s) + CO2(g) --- solid to solid & gas - most entropy here

(2) 2 Mg(s) + O2(g) --> 2 MgO(s) solid & gas to a solid

(3) H2O(g) --> H2O(l) gas to a liquid

(4) CO2(g) --> CO2(s)   gas to a solid

Thus the correct option is 1.

To know more about entropy, visit;

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What do scientists usually do if they can't draw clear conclusions?

Answers

collect more data to support their hypothesis


They use the Scientific Method.
The Scientific Method is made up of steps scientists take to draw a conclusion
Step 1: Form a Question
Step 2: Research the Question
Step 3: Form a Hypothesis (educated guess)
Step 4: Conduct an Experiment (use quantitative and qualitative data)
Step 5: Form Your Conclusion Based on Results

This should help....


Which of the following is TRUE about a physical change in matter?O A physical change changes the identity of the substance
O A physical change does not change the chemical formula of the substance
O A physical change has similar characteristics as a chemical change.
A physical change is a change in how the substances react with other substances.

Answers

The correct answer is physical change does not change the chemical formula of the substance.

What is a physical change?

  • A physical change is one in which only the physical state of matter is altered.
  • Its chemical characteristics have not changed.
  • A physical change is usually brought about by increasing the temperature or exerting pressure, or both.
  • The original state of matter is restored by reversing the condition, that is, lowering the temperature, lowering the pressure, or both.
  • Physical changes, in other words, are reversible.

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Answer:

B.  a physical change does not change the chemical formula of the substance

Explanation:

Physical change does not change the substance or identity of an object

How does the number of molecules in 1 mol of oxygen compare with the number of molecules in 1 mol of nitrogen?1) 1 mol of oxygen has fewer molecules.2) 1 mol of oxygen has more molecules.3) Each sample has the same number of molecules.4) The molecules cannot be compared without knowing the mass.

Answers

The number of molecules in 1 mol of oxygen compare with the number of molecules in 1 mol of nitrogen is that each sample has the same number of molecules. The answer is number 3

Answer:

3) Each sample has the same number of molecules

Explanation:

1 mol are 6,022x10²³ particles. Moles of a chemical substance represent the number of molecules that this chemical has.

Thus, one mol of oxygen are 6,022x10²³ molecules of oxygen and one mol of nitrogen are 6,022x10²³ molecules of nitrogen.

Right answer is:

3) Each sample has the same number of molecules.

I hope it helps!

What does the name 2–butene tell you about this hydrocarbon's molecular structure?A.There are two carbon atoms and all single carbon bonds.

B. There are two carbon atoms and a double carbon bond.

C. There are three carbon atoms and a double carbon bond that starts on the second carbon atom.

D. There are four carbon atoms and a double carbon bond that starts on the second carbon atom.

Answers

Option D. There are four carbon atoms and a double bond that starts on the second carbon atom.

Methane: one carbon
Ethene: two carbons
Propene: three carbons
Butene: four carbons.
Pentene: five carbons

The suffix - ene is used for double bonds.

The number 2- indicates the place of the carbon on which the double bond is located.

Gradpoint answer:  a four-carbon hydrocarbon with a double bond between the second and third carbon atoms